Sign up to receive free email alerts when patent applications with chosen keywords are publishedSIGN UP

Abstract:

A decorative member (1A) includes: a resin layer (2) having a front
surface (2b) and a back surface (2a); and a reflective layer (3) formed
on the back surface (2a) of the resin layer (2). The back surface (2a) of
the resin layer (2) includes a receding surface (21) formed therein. The
receding surface recedes gradually toward the front surface (2b) to
change a thickness of the resin layer (2). A pigmented layer (4)
configured so that lightness/depth of color thereof changes in accordance
with the change in the thickness of the resin layer (2) is provided
between the back surface (2a) of the resin layer (2) and the reflective
layer (3).

Claims:

1. A decorative member comprising: a colored light-transmissive resin
layer having a front surface and a back surface, the back surface
including a receding surface formed therein, the receding surface
receding gradually toward the front surface to change a thickness that is
a distance between the front surface and the back surface; a reflective
layer formed on the back surface of the resin layer so as to cover the
receding surface; and a pigmented layer interposed between the back
surface of the resin layer and the reflective layer, the pigmented layer
being configured so that lightness/depth of color thereof changes in
accordance with the change in the thickness of the resin layer.

2. The decorative member according to claim 1, wherein on the receding
surface, the pigmented layer is composed of dots whose density increases
as the thickness of the resin layer increases.

3. The decorative member according to claim 1, wherein the receding
surface is curved continuously along at least one direction perpendicular
to a thickness direction of the resin layer so as to be convex toward the
front surface.

4. The decorative member according to claim 3, wherein the receding
surface is a concave surface forming a depression that opens while
broadening.

5. The decorative member according to claim 4, wherein the concave
surface has a cylindrical shape curved continuously along the one
direction perpendicular to the thickness direction of the resin layer.

6. The decorative member according to claim 4, wherein the concave
surface has a dome shape curved continuously along two directions
perpendicular to each other and to the thickness direction of the resin
layer.

7. The decorative member according to claim 1, wherein the back surface
of the resin layer includes a reference surface outside the receding
surface, and the reference surface also is covered with the reflective
layer.

8. The decorative member according to claim 7, wherein the reference
surface is a flat surface perpendicular to a thickness direction of the
resin layer.

9. The decorative member according to claim 1, wherein the front surface
of the resin layer is a flat surface perpendicular to a thickness
direction of the resin layer.

10. The decorative member according to claim 1, wherein the reflective
layer has a metallic color.

11. The decorative member according to claim 10, wherein the reflective
layer is composed of a coating film formed by coating or printing, a
metal film formed by vapor deposition, or a sheet bonded to the back
surface of the resin layer.

12. The decorative member according to claim 1, wherein the decorative
member extends in a specified direction and the receding surface extends
in a longer direction of the decorative member.

Description:

TECHNICAL FIELD

[0001] The technique disclosed herein relates to a decorative member that
exhibits a pattern having a raised three-dimensional appearance.

BACKGROUND ART

[0002] Conventionally, as a decorative member for realizing a design with
a three-dimensional visual effect, Patent Literature 1 has disclosed a
decorative member 100 as shown in FIG. 8. In the decorative member 100, a
transparent or translucent resin plate 200 has a back surface serrated
with steep slopes 210 with a large inclination angle and gentle slopes
220 with a small inclination angle repeated alternately, and the back
surface is covered with a colored layer 300.

[0003] The colored layer 300 has light reflecting capability. At portions
of the colored layer 300 facing the gentle slopes 220, light that has
entered the resin plate 200 through its front surface is reflected by the
colored layer 300 so as to return to a front side. However, at portions
of the colored layer 300 facing the steep slopes 210, the light is
reflected by the colored layer 300 so as to veer in a lateral direction.
This allows the colored layer 300 to look dark at portions corresponding
to the steep slopes 210, forming a three-dimensional stripe pattern
appearance.

CITATION LIST

Patent Literature

[0004] PTL 1: JP 58 (1983)-7494 B

SUMMARY OF INVENTION

Technical Problem

[0005] In Patent Literature 1, as is apparent from the fact that the term
"colored layer" is used therein, the colored layer 300 represents the
color of the pattern of the decorative member 100. However, in such a
case where the colored layer 300 represents the color of the pattern of
the decorative member 100, the ridges formed by providing the colored
layer 300 along the two slopes 210, 220 do not look raised well, and the
three-dimensional visual effect is not so high.

[0006] In view of the foregoing, the technique disclosed herein is
intended to provide a decorative member with a high three-dimensional
visual effect.

Solution to Problem

[0007] The above-mentioned problems is solved by a decorative member
including: a colored light-transmissive resin layer having a front
surface and a back surface, the back surface including a receding surface
formed therein, the receding surface receding gradually toward the front
surface to change a thickness that is a distance between the front
surface and the back surface; a reflective layer formed on the back
surface of the resin layer so as to cover the receding surface; and a
pigmented layer interposed between the back surface of the resin layer
and the reflective layer, the pigmented layer being configured so that
lightness/depth of color thereof changes in accordance with the change in
the thickness of the resin layer.

ADVANTAGEOUS EFFECTS OF INVENTION

[0008] In the above-mentioned decorative member, by changing, with the
receding surface, the thickness of the colored resin layer, it is
possible to form, on a convex portion formed by providing the reflective
layer along the receding surface, a gradation of color that is pale at a
thin portion of the resin layer and deep at a thick portion of the resin
layer. Moreover, because of the transmission loss of light in the resin
layer and the reflection of light by the reflective layer, the convex
portion of the reflective layer along the receding surface looks bright
at the thin portion of the resin layer and dark at the thick portion of
the resin layer. With such a gradation having not only the
lightness/depth of color but also the contrast of light utilizing the
reflection of light, the convex portion of the reflective layer has a
distinctly raised appearance. Thereby, a high three-dimensional visual
effect can be obtained.

[0009] Furthermore, in the above-mentioned decorative member, the
pigmented layer interposed between the resin layer and the reflective
layer makes it possible to reduce the thickness of the resin layer while
maintaining the high three-dimensional visual effect.

BRIEF DESCRIPTION OF DRAWINGS

[0010]FIG. 1 is a perspective view of a decorative member according to
Embodiment 1 of the present invention when viewed from a back side
thereof.

[0011]FIG. 2 is a cross-sectional view of FIG. 1 taken along the line
II-II.

[0012]FIG. 3 is a cross-sectional view of FIG. 1 taken along the line
III-III.

[0013]FIG. 4 is a view showing an appearance of the decorative member
shown in FIG. 1 when viewed from a front side thereof.

[0014] FIG. 5A is a view showing an appearance of a decorative member
according to Embodiment 2 of the present invention when viewed from a
front side thereof, and FIG. 5B is a cross-sectional view of the
decorative member.

[0015]FIG. 6A is a perspective view of a modified decorative member when
viewed from a back side thereof, and FIG. 6B is a cross-sectional view of
the decorative member.

[0016]FIG. 7 is a cross-sectional view of another modified decorative
member.

[0017]FIG. 8 is a cross-sectional view of a conventional decorative
member.

DESCRIPTION OF EMBODIMENTS

[0018] Hereinafter, embodiments of the present invention will be described
with reference to the drawings.

Embodiment 1

[0019] FIGS. 1 to 3 show a decorative member 1A according to Embodiment 1
of the present invention. The decorative member 1A has an approximately
rectangular plate-like shape extending in a specified direction. The
decorative member 1A has a resin layer 2 on a front side (on a bottom
side in FIGS. 1 to 3), and a reflective layer 3 on a back side (on a top
side in FIGS. 1 to 3).

[0020] The resin layer 2 is colored and light-transmissive. More
specifically, the resin layer 2 allows light in a specified wavelength
range of a visible light range to transmit therethrough, and absorbs or
reflects light other than this. The color of the resin layer 2 is not
particularly limited. Preferably, a relatively deep color (for example:
black, red, and blue; or ACRYLITE produced by Mitsubishi Rayon Co., Ltd.,
color tone No. 530 (blue smoke), No. 540 (green smoke), No. 550 (brown
smoke), and No. 83 (gray smoke)) is used. As the material composing the
resin layer 2, various polymers, such as an acrylic resin, polycarbonate,
ABS (acrylonitrile butadiene styrene), polyamide, and nylon, can be used
independently or in combination as a polymer alloy.

[0021] The resin layer 2 has a front surface 2b that is one surface in a
thickness direction thereof, and a back surface 2a that is the other
surface in the thickness direction. The front surface 2b is a flat
surface perpendicular to the thickness direction of the resin layer 2. In
the back surface 2a, a receding surface 21 is formed. The receding
surface 21 recedes gradually toward the front surface 2b to change a
thickness that is a distance between the front surface 2b and the back
surface 2a. In the present embodiment, the back surface 2a includes,
outside the receding surface 21, a reference surface 22 that is parallel
to the front surface 2b (in other words, the reference surface 22 is a
flat surface perpendicular to the thickness direction of the resin layer
2.)

[0022] The receding surface 21 is curved continuously along at least one
direction perpendicular to the thickness direction of the resin layer 2
so as to be convex toward the front surface 2b. As stated herein, the
phrase "to be curved continuously" means that the gradient of a tangent
of a cross-sectional shape of the receding surface 21 in a direction in
which the receding surface 21 is curved varies in one-way direction from
one end to the other end of the cross-sectional shape substantially
continuously. It should be noted that the receding surface 21 may be
formed in a linear curving manner with a constant curvature, or in a
non-linear curving manner with a variable curvature. The term
"substantially" indicates a concept including a case where: concave and
convex portions such as those remaining on the surface during processing
are ignored; and the gradient of a tangent of a cross-sectional shape of
the receding surface 21 varies in one-way direction from one end to the
other end of the cross-sectional shape continuously in a shape
recognizable by human vision.

[0023] In the present embodiment, the receding surface 21 is a concave
surface forming a depression that opens while broadening. In other words,
the cross-sectional shape of the receding surface 21 in the direction in
which the receding surface 21 is curved extends from one end to the other
end so as to come closer to the front surface 2b and then go away
therefrom. Furthermore, the concave surface of the present embodiment has
a dome shape curved continuously along a longer direction and a shorter
direction of the decorative member 1A (two directions perpendicular to
each other and to the thickness direction of the resin layer 2.) The
reference surface 22 surrounds the receding surface 21.

[0024] The shape of the receding surface 21 in a plan view is not
particularly limited. Preferably, the receding surface 21 extends in the
longer direction of the decorative member 1A. For example, the shape of
the receding surface 21 may be an elliptical shape or a strip-like shape
with both ends being roundish, when viewed from the thickness direction
of the resin layer 2.

[0025] A peripheral portion of the receding surface 21 may be joined
directly to the reference surface 22 angularly so as to form a ridgeline
with the reference surface 22. Alternatively, there may be provided a
joint, having a cross-sectional shape that is convex in the direction
opposite to that of the receding surface 21, annularly between the
peripheral portion of the receding surface 21 and the reference surface
22, and the peripheral portion of the receding surface 21 may be joined
smoothly to the reference surface 22 via the joint.

[0026] The resin layer 2 as mentioned above can be molded by a molding
method such as injection molding, heating compression molding, and a
combination of extrusion molding and heating compression molding. In
molding the resin layer 2, it is preferable to use a mirror-finished
metal mold in order to prevent the irregular reflection of light by the
front surface 2b and to enhance the texture.

[0027] The reflective layer 3 is formed on the back surface 2a of the
resin layer 2 so as to cover the receding surface 21 and the reference
surface 22. The reflective layer 3 serves to reflect the light that has
transmitted through the resin layer 2. Preferably, the reflective layer 3
essentially blocks light in the visible light range (approximately 400 to
750 nm) from transmitting therethrough, and has high reflectance to light
essentially throughout the visible light range. From the viewpoint of
regularly reflecting the light that has transmitted through the resin
layer 2, a front surface of the reflective layer 3 contacting the
receding surface 21 and the reference surface 22 of the resin layer 2
preferably is a lustrous smooth surface. For example, the transmittance
of the reflective layer 3 to visible light preferably is 5% or less, more
preferably 1% or less, and particularly preferably 0.1% or less. The
reflectance and the smooth surface are expressed in terms of a gloss
(luster) value of the front surface of the reflective layer 3. When the
gloss value in the case where the brightness difference between incident
light and receiving light is 10%, with the incident angle being 60 degree
and the receiving angle being -60 degree on a glass surface (with a
refractive index of 1.567), is taken as 100, the gloss value of the front
surface of the reflective layer 3 preferably is 200 or more, more
preferably 700 or more, and particularly preferably about 800.

[0028] Furthermore, the reflective layer 3 preferably has a metallic
color. The reflective layer 3 can be composed of, for example: a coating
film formed by coating a coating material containing a metallic pigment
or a metallic colorant, or by printing a metallic ink; a metal film
formed by vapor-depositing metal such as aluminum; or a metallic-colored
sheet bonded to the back surface 2a of the resin layer 2.

[0029] In the present embodiment, a pigmented layer 4 further is provided
between the back surface 2a of the resin layer 2 and the reflective layer
3. The pigmented layer is configured so that lightness/depth of color
thereof changes in accordance with the change in the thickness of the
resin layer. The pigmented layer 4 as a whole allows light in a visible
light range to transmit therethrough. In the pigmented layer 4, the
amount of light in a visible light that transmits a deep-colored portion
is smaller than that transmitting a pale-colored portion.

[0030] Specifically, on the receding surface 21, the pigmented layer 4 is
composed of dots whose density increases as the thickness of the resin
layer 2 increases. Such dots can be formed by a printing technique using
an ink. As the printing technique, gravure printing or screen printing is
used suitably. On the reference surface 22, the pigmented layer 4 may be
composed of dots with a density comparable to that of the dots on the
peripheral portion of the receding surface 21, or may be composed of a
coating film formed by printing the ink on the entire reference surface
22.

[0031] In the decorative member 1A of the present embodiment described
above, by changing, with the receding surface 21, the thickness of the
colored resin layer 2, it is possible to form, on the convex portion
formed by providing the reflective layer 3 along the receding surface 21,
a gradation of color that is pale at the thin portion of the resin layer
2 and deep at the thick portion of the resin layer 2 as shown in FIG. 4.
Moreover, because of the transmission loss of light in the resin layer 2
and the reflection of light by the reflective layer 3, the convex portion
of the reflective layer 3 along the receding surface 21 looks bright at
the thin portion of the resin layer 2 and dark at the thick portion of
the resin layer 2. With such a gradation having not only the
lightness/depth of color but also the contrast of light utilizing the
reflection of light, the convex portion of the reflective layer 3 has a
distinctly raised appearance. Thereby, a high three-dimensional visual
effect can be obtained.

[0032] Furthermore, in the decorative member 1A of the present embodiment,
the pigmented layer 4 interposed between the resin layer 2 and the
reflective layer 3 makes it possible to reduce the thickness of the resin
layer 2 while maintaining the high three-dimensional visual effect. In
the case where the pigmented layer 4 is not provided, the thickness of
the resin layer 2 is the only factor for defining the lightness/depth of
color in the gradation. Therefore, in order to obtain a high
three-dimensional visual effect, it is necessary to increase the
thickness of the resin layer 2 to some extent and increase the level
difference between the top and the bottom of the receding surface 21 (the
distance over which the receding surface 21 recedes in the thickness
direction of the resin layer 2). However, in the case where the level
difference in the receding surface 21 is increased in this way, warpage
and weld occur when the resin layer 2 is molded by, for example,
injection molding, which decreases the yield. In contrast, in the case
where the pigmented layer 4 is provided between the resin layer 2 and the
reflective layer 3 as in the present embodiment, the lightness/depth of
color in the gradation can be defined also by the lightness/depth of
color of the pigmented layer 4. This makes it possible to obtain a
comparable three-dimensional visual effect even when the level difference
in the receding surface 21 is reduced and the thickness of the resin
layer 2 is reduced. As a result, it is possible to suppress a decrease in
the yield at the time of molding the resin layer 2 and to reduce the
manufacturing cost.

[0033] In addition, in the decorative member 1A of the present embodiment,
since the receding surface 21 is curved continuously, it is possible to
change gradually and minutely the lightness/depth of color and the
contrast of light in the gradation from the thin portion of the resin
layer to the thick portion of the resin layer. Moreover, the degree of
the gradation formed on the convex portion of the reflective layer 3
varies in accordance with the angle at which the decorative member 1A is
viewed. Thereby, the three-dimensional visual effect can be accentuated
further.

[0034] Furthermore, in the decorative member 1A of the present embodiment,
the reference surface 22 is provided outside the receding surface 21. The
normal direction of the front surface of the reflective layer 3 becomes
lateral gradually from the bottom of the receding surface 21 toward the
peripheral portion, and accordingly the colored resin layer 2 looks
darker gradually. At a portion right above the peripheral portion of the
receding surface 21, the darkness reaches its peak and the resin layer 2
looks blackish. In contrast, at the thickest portion at which the
thickness of the resin layer 2 defined by the reference surface 22 is
largest, the reflective layer 3 is parallel to the front surface 2b. For
this reason, at the thickest portion, the colored resin layer 2 looks
deeper in color than at the thinnest portion at which the thickness of
the resin layer 2 defined by the bottom of the receding surface 21 is
smallest, and paler than at the portion right above the peripheral
portion of the receding surface 21. Thereby, the darkness at the
peripheral portion of the receding surface 21 is accentuated in
comparison with the reference surface 22, and a higher three-dimensional
visual effect can be obtained.

Embodiment 2

[0035] Next, FIGS. 5A and 5B show a decorative member 1B according to
Embodiment 2 of the present invention. In the present embodiment, the
same components as those in Embodiment 1 are indicated with the same
reference numerals, and the descriptions thereof are omitted.

[0036] In the decorative member 1B of the present embodiment, a concave
surface forming a groove-like depression extending in a longer direction
of the decorative member 1B is formed, as the receding surface 21, in the
back surface 2a of the resin layer 2. That is, the concave surface has a
cylindrical shape curved continuously along only a shorter direction (one
direction perpendicular to the thickness direction of the resin layer 2)
of the decorative member 1B. Thereby, a gradational pattern, as shown in
FIG. 5A, having a three-dimensional visual effect is expressed in the
decorative member 1B.

[0037] Also in the gradation shown in FIG. 5A, the lightness/depth of
color and the contrast of light in the gradation change gradually and
minutely from the thin portion of the resin layer to the thick portion of
the resin layer, as in Embodiment 1. Furthermore, outside the receding
surface 21, the colored resin layer 2 looks to have an intermediate color
and brightness of the gradation. Therefore, the same effects also can be
obtained in Embodiment 2 as in Embodiment 1.

Modification

[0038] Although the front surface 2b of the resin layer 2 is a flat
surface in Embodiments 1 and 2, the front surface 2b of the resin layer 2
may be bowed or may be formed with an undulation, for example. Moreover,
the reference surface 22 of the back surface 2a of the resin layer 2 does
not necessarily have to be a flat surface perpendicular to the thickness
direction of the resin layer 2. For example, in the case where the front
surface 2b is bowed, the reference surface 22 may be a bowed surface
parallel to the front surface 2b.

[0039] Alternatively, like a modified decorative member 1C shown in FIGS.
6A and 6B, the receding surface 21 may be formed over the entire back
surface 2a of the resin layer 2. However, with the reference surface 22
being provided outside the receding surface 21 as in Embodiments 1 and 2,
the darkness at an edge of the receding surface 21 is accentuated in
comparison with the reference surface 22 and a higher three-dimensional
visual effect can be obtained.

[0040] Furthermore, the receding surface 21 does not necessarily have to
be a concave surface forming a depression that opens while broadening. As
shown in FIG. 6B, the receding surface 21 may have a cross-sectional
shape that extends from one end to the other end so as to only come
closer to the front surface 2b, in the direction in which the receding
surface 21 is curved.

[0041] Moreover, the receding surface 21 does not necessarily have to be
curved along at least one direction perpendicular to the thickness
direction of the resin layer 2 so as to be convex toward the front
surface 2b. For example, like a modified decorative member 1D shown in
FIG. 7, the receding surface 21 may be inclined linearly toward the front
surface 2b. However, with the cross-sectional shape of the receding
surface 21 being a curved line as in Embodiments 1 and 2, the degree of
the gradation formed on the convex portion of the reflective layer 3
varies in accordance with the angle at which the decorative member 1A is
viewed, and thereby the three-dimensional visual effect can be
accentuated further.

[0042] The decorative member according to the present invention does not
necessarily have to have a shape extending in a specified direction. For
example, it may have a regular polygonal shape in a plan view, or a
rectangular frame shape that opens in the thickness direction of the
resin layer 2.

Examples

[0043] Hereinafter, the present invention will be described in detail with
reference to Examples, but the present invention is not restricted to
these Examples.

Example

[0044] A resin layer with shaped as shown in FIGS. 5A and 5B was molded by
injection molding using an acrylic resin (ACRYLITE produced by Mitsubishi
Rayon Co., Ltd., color tone No. 530 blue smoke). From the viewpoint of
mechanical strength and moldability, the thickness of the thinnest
portion defined by the bottom of the receding surface 21 was set to 1.0
mm, and the thickness of the thickest portion defined by the reference
surface 22 was set to 2.0 mm. In the back surface of this resin layer,
dots with a diameter of 10 μm were formed on the receding surface by
gravure printing using a black ink so that the density of the dots
changes gradually from 0 dots/mm2 to 19000 dots/mm2 from the
bottom of the receding surface to the peripheral portion of the receding
surface, and the ink was printed on the entire reference surface. Thus, a
pigmented layer was formed. Thereafter, a coating material containing a
metallic pigment (SUPER BRIGHT SILVER 2000, produced by Dai Nippon Toryo
Co., Ltd.) was applied on the pigmented layer to form a coating film
serving as the reflective layer. Thereby, a decorative member was
obtained.

Comparative Example 1

[0045] A decorative member was obtained in the same manner as in Example,
except that the thickness of the thickest portion of the resin layer was
set to 3.0 mm and no pigmented layer was formed.

Comparative Example 2

[0046] A decorative member was obtained in the same manner as in the
Example, except that no pigmented layer was formed.

[0047] (Bright/Dark Ratio)

[0048] The decorative members of Example and Comparative Examples were
measured for bright/dark ratio. The measurement of the bright/dark ratio
was made by measuring the reflectances of the thinnest portion and the
thickest portion in increments of 10 nm in the wavelength range of 400 nm
to 740 nm with a spectrophotometer (CM-3600d, manufactured by Konica
Minolta Holdings, Inc.), and calculating the ratio between the averages
thereof. Table 1 shows the results.

[0049] In Comparative Example 1, the level difference in the receding
surface formed in the back surface of the resin layer is large and a high
three-dimensional visual effect can be obtained. However, the large level
difference in the receding surface causes warpage and weld to occur,
decreasing the yield at the time of molding the resin layer. In
Comparative Example 2, the yield at the time of molding the resin layer
is less decreased because the level difference in the receding surface is
small, but the bright/dark ratio is lowered significantly in comparison
with Comparative Example 1, deteriorating the three-dimensional visual
effect significantly.

[0050] In contrast, in Example, even with the small level difference in
the receding surface, it is possible to keep the bright/dark ratio
comparable to that of Comparative Example 1 and to obtain a high
three-dimensional visual effect.

INDUSTRIAL APPLICABILITY

[0051] The present invention is useful for decorative members to be used
for providing high quality decoration to casings of electrical devices,
etc.

Patent applications by Shuji Yamashita, Nara JP

Patent applications by Suguru Nakao, Hyogo JP

Patent applications by Takehiko Yamashita, Hyogo JP

Patent applications by PANASONIC CORPORATION

Patent applications in class Containing metal or metal compound

Patent applications in all subclasses Containing metal or metal compound